This invention relates to hand tools for turning threaded connectors, such as machine screws, bolts and nuts, and especially to wrenches with a reversing ratchet-and-pawl mechanism. More particularly, the invention relates to a reversing-ratchet wrench for various interchangeable socket heads with an improved forward-reverse selector mechanism that simplifies assembly and facilitates the retaining of the selector mechanism in the pawl carrier.
Wrenches with reversing-ratchet drive are well-known in the art and are commonly used as socket tools. The inner end, or fulcrum end, of the wrench, usually has a male-type connector, or stud, that fits in a square female recess in various interchangeable socket heads with which the wrench is to be used. Wrenches of this general construction are disclosed in U.S. Pat. Nos. 3,393,587 and 3,881,376.
In wrenches of this type, internal ratchet teeth are generally formed in an opening in the fulcrum end of the wrench and a cylindrical pawl carrier with a square drive stud on one end is mounted in the opening for rotation about the axis of turn on the wrench. The pawl carrier also has a central axial bore in the end opposite the drive stud and a lateral slot cut in one side perpendicular to the axis of the pawl carrier and extending to the axial bore. A double pawl is pivotally mounted within the slot and is adapted for selective driving engagement with the internal ratchet teeth. The pawl is pivotally connected by a pivot pin that extends therethrough parallel to the axis of turn and that has its opposite ends journaled in the pawl carrier.
A ratchet drive selector mechanism is used to control the position of the double pawl to provide either forward or reverse ratchet drive. The selector mechanism has a hub that is pivotally mounted in the axial bore in the pawl carrier and the hub has a transverse bore that extends partly therethrough and is adapted to receive a plunger with a length less than the depth of the bore. The plunger is biased to an extended position by a helical spring that urges the plunger radially outward into the lateral slot and against the double pawl.
In the assembly of prior art socket wrenches of the type described, the plunger and spring are pressed into the transverse bore in the hub until the plunger is entirely within the bore. Then the hub is inserted in the central axial bore in the pawl carrier until the transverse bore in the hub registers with the lateral slot. At this point, the plunger is released to extend radially outward into the lateral slot and into engagement with the pawl to urge the pawl into either its forward drive or reverse drive condition, depending upon the position to which the selector mechanism is turned. It will be noted that in prior art wrenches of this type, the pawl must first be mounted in the pawl carrier before the selector mechanism and pawl carrier are assembled together. One problem with this type of construction is the certain difficulties occur during machining and assembly that consequently require a time-consuming procedure on the part of the assembler.
The reversing-ratchet socket wrench design of the present invention, however, reduces the difficulties indicated above and affords other features and advantages heretofore not obtainable.